Method and apparatus for shaping tubing



1932- o. w. SIEBERT ET AL 1,891,785

METHOD AND APPARATUS FOR SHAPING TUBING Filed Jan. 12, 1931 5 0% fdc'eber 'cfimwi r-1M:

OTTO W. SIEBERT AND CARL J. BJORSON, OF GARDNER, MASSACHUSETTS, ASSIGNOBIS Patented Dec. 20, 1932 UNITED STATES PATENT OFFICE,

MASSACHUSETTS TO 0. W. SIEBERT COMPANY, OF GARDNER, MASSACHUSETTS, A CORPORATION 01- METHOD AND APPARATUS FOR- SHAPING TUBING Application filed January 12, 1931. Serial No. 508,113.

This invention relates to a method and ap paratus to be used in changing the cross section of hollow metal tubing. The invention is particularly applicable for use with metal tubing having a longitudinal seam, the edges of which are welded or brazed or otherwise secured together. When an attempt is made to flatten such a piece of tubing or to change it to elliptical or oval cross section, the welded edges frequently separate with a hinge-like action about the outer edge of the weld. i 7

It is the object of our invention to provide a method and apparatus for changing the cross section of metal tubing in such manner that the portion of tubing adjacent the longitudinal weld shall retain substantially its original contour, while distortion of thetubing from its original contour occurs entirely in continuous metal removed from the seam or joint.

A more specific object of our invention is to provide dies for such purposes which engage the tubing along spaced parallel longitudinal lines or edges only. a

Fig. 2 is a sectional elevation of a pair of dies engaging the circular tubing;

Fig. 3 is a similar view but showing the position of the parts after the operation of the dies is completed;

Fig. 4 is a view similar to Fig. 1 but showing the tubing after the change in cross section" 5 is a sectional elevation showing dies for producing a tubing of semi-oval section;

Fig. 6 indicates the productionof a fully flattened tubing from the product shown in Fig. 4 or Fig. 5, and

Fig. 7 indicates the difficulty heretofore encountered in carrying out thls pressoperation.

It has been the usual procedure in flattening tubing or changing its section, to pro+ vide a pair of dies 10 and 11 '(Fig. 7) having '7 continuous concave work-engaging surfaces. When such dies engaged a plece of tubing along a longitudinal seam, thepressure of the dies against the welded portion frequently caused the partsto separate and bend inward along the seam, as indicated in Fig. 7 Qde:

forming .thetubing and opening a longitudi= nal crack therein.

In our improved method of'operation; we avoid thedefects of the former procedure by.

providing dies and 21 having spacedparallel edge portions 22 separated by a deep're-' cess- 23. Theedges'22 engage the tubeT along lines relatively remote from the seam or weld W and we thus transform the tube T to the substantially oval or elliptical sec-' Consequently there is no substantial tendency to open the weld W and there isno hinge action about the joint such as occurred when using the old style dies indicatedin Fig.

7. Consequently a welded tube may be readily transformed to a flattened elliptical or oval cross sectionwithout opening or weakening the longitudinal weld or seam therein.

This is an important advance in the art of using welded or brazed tubing, as it permits the use of such tubing in many places where a seamless tubing was heretofore required. Such seamless tublng is very much more expensive than welded or brazedtubing and in many places the cost is prohibitive. In Fig. 5, we show the application of our invention to the production of a tubing T of semi-oval cross section by the use of a sin gle recessed die 30 only, the other die 31 being I fiat. It will be understood that the blank tubing is positioned so that the weld or seam'will' be located in the recess of the die 30 asthe pressure thereof is applied to the tubing."

The tubing T or T produced as shown in inc 7 V by the use of a pair of flat dies 40 and 41,

which have much less tendency to open the seams in this case than they would have if applied direct to the round tubing T. V

Having-thus described our invention and the manner in which it may be practiced, we

do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what we claim is 7 1. The method of changing the cross section of circular tubing which consists .in applying pressure along two spaced parallel lines at one side of the tubing and in a direction substantially perpendicular to the plane of said parallel lines, suohpressure being re,- sisted along two spaced and opposed parallel lines at the opposite side of the tubing, the tubing being free from direct pressure hetween the first two lines and also between the last two lines.

2. The method of changing the cross section of circular tubing which consists in applying pressure along two spaced parallel lines'at one side of the tubing and in a direc- 'tion substantially perpendicular to the plane of said parallel lines, and in opposing the pressure on the other side of said tubing, the tubing being free from direct pressure between said parallel lines.

3. Apparatus for use in changing the cross section of circular tubing to a substantially elliptical cross section which comprises a pair of dies, each having two parallel angular tube-engaging edge portions substantially spaced apart by an intervening recessed nonengaging portion, the tube-engaging portions of said diesbeingpositioned directly opposite to each other, and the recessed portions of said dies also being positioned directly opposite to each other when said dies are applied to a tube. V

In testimony whereof we have afiixed our signatures.

- OTTO W. SIEBERT.

CARL J. BJORSON.

hereunto 

